[1] Natl Canc Ctr Hosp East, Chiba, Japan
[2] Kobe Univ Hosp, Div Med Oncol & Hematol, Dept Med, Kobe, Hyogo, Japan
[3] Grad Sch Med, Kobe, Hyogo, Japan
[4] Shizuoka Canc Ctr, Shizuoka, Japan
[5] Aichi Caner Ctr, Nagoya, Aichi, Japan
[6] Aichi Canc Ctr Hosp, Nagoya, Aichi, Japan
[7] Ctr Canc Chemotherapy, Tokyo, Japan
[8] Japanese Fdn Canc Res, Canc Inst Hosp, Tokyo, Japan
[9] Hyogo Canc Ctr, Dept Med Oncol, Akashi, Hyogo, Japan
[10] Hokkaido Univ, Grad Sch Med, Dept Otolaryngol Head & Neck Surg, Sapporo, Hokkaido, Japan
[11] Hokkaido Univ Hosp, Dept Med Oncol, Sapporo, Hokkaido, Japan
[12] Gunma Prefectural Canc Ctr, Ota, Japan
[13] Gunma Prefectural Canc Ctr, Div Resp Med, Ota Shi, Japan
[14] Nara Hosp Kinki Univ, Fac Med, Ikoma, Japan
[15] Kinki Univ, Dept Med Oncol, Fac Med, Osaka, Japan
[16] Saitama Canc Ctr Hosp, Dept Gastroenterol, Saitama, Japan
[17] Tohoku Univ, Sendai, Miyagi, Japan
[18] Yokohama City Univ, Dept Biostat, Yokohama, Kanagawa, Japan